Is this table linear or nonlinear?

Question

This is the actual table,

  

x           y
-3         10
-1          2
1           2
3           10

 

Now my teacher has told me this is a linear function because there are no repeating numbers in the x value. According to Khan Academy though this table is nonlinear because the rate of change in x and y is not constant. Please help.

Answer 1

It is a "function" because each x-value has one and only one y-value.  However, it is a non-linear function.  A linear function has a constant rate of change, Δy/Δx.

Answer 2

Its non linear as y/x value is not constant

Thus all the points will not fall on the same line